Chapter 9 part 2 Midterm 2 Flashcards
Where does everything in left visual field get represened?What about right?
right V1
left V1
What are the two types of fields? describe them?
visual field; the region of the visual world that is collected by eyes
receptive field; the places in retina that are receptive to info from a specific side, is region of the visual world that stimulates a receptor cell or neuron
Is there spatial Organization in the LGN V1?
Yes, in the LGN the information in the visual field retains it’s postion when sent to the LGN
The central part of the visual field is located where in the brain?
back of the brain
The peripheral areas of the visual field are located where in the brain?
more anteriorly
Where is the top part of the visual field represented in the occipital lobe?
In the lower part, just below the primary V1
What is the optical hierarchy of cells? What receptive fields combine to eventually create the recpetive field of a single V1 cell?
recepitve field of ganglion cells combine to give rise to the receptive field of a single LGN cell, which combine to give receptive field of a V1 cell
The amount of neural tissue responisible for a particular function is equivalent to what? (ON TEST)
is equivalent to the amount of neural processing (compexity) of that function
The occipital lobe has no corpus collusum connections, what does this mean?
the brain has to independently use info from the right and left in order to create images
What do cells along the midline create?
They create the image along the midline
Why do optical illusions work?
Differences in color, contrasts, and shapes lead to them
What is neural activity coded by?
action potential production
What is action pot production that always happens?
baseline
What increases basline action pot production?
excitation and stimulation
Can the presentation of a stimulus result in an inhibition of action pot production?
Yes
Can the absence of action pot tell you if something is there or not there?
yes
What cell make up optic nerve?
retinal ganglion cells
How do retinal cells code for shapes of a specific object?
We look at object, encode how shapes contour and change
light then stimuates retina to create signals, some cells are on center and some are off center, if light hits an on cell an action potential fires, if it hits off cells it will not fire.
How is a big picture of the visual field represented through off an oncenter cells?
receptive field of ganglion cells overlap, so light can hit on and off at the same time which allows you to create an accurate picture of the thing ur looking at
What is luminance contrast?
we have ganglion cells that fire depending on how contrast changes which allows us to differentiate between color, every single contrast has cells that encode differences in colors.
How does the angle of light hitting simple cells impact the action potentials?
If you hit both on and off cells you get no repsonse
Who discovered angle of cells matter for action potentials?
Hubel and Weisel
Why does the cell response rate drop when you focus on one color?
less contrast, cell response rate is heightened at more contrast
How does the angling of simple cells themselves effect action potentials?
if it makes stimulus light both on and off portions you get no response, if you get light just hitting on you see large response
How does the angle of light hitting complex cells in the primary visual cortex effect the action potentials?
Complex cells have an angular component, stimulus at certain angle increases or decreases whether there’s a response and the magnitude of the response.
at 60 is weak
at 45 is strong
How does light moving effect hypercomplex cells in the visual cortex?
the more it goes into off the less response you get, unlike simple cells which when light hits off and on you get no response.
Input from layer four of stelate cells project where?
layer three and five
in the visual cortex where s info spatially encoded?
is spatially encoded into columns
Are the columns in V1 specific for the right and left eye ?
yes
Say some objects have the same orientation where will they be encoded in V1?
in the same columns
Every neuron in the same column has the what?
the same orientation bias
An object is the temproal lobe is repsentened by how many neurons?
several
neurons in the temporal lobe respond to what?
categories in shape
what is stimulance equivalence in the temporal lobe?
you see things as the same even if viewed at diff angles
Why does seeing red and blue lead to seeing greenish yellowish? Opponent process thoery?
you tire out cones, makes you see opposite colors
How does the response of ganglion cells alter when red light hits them vs green?
if red in on you get strong response
if red in off and green on, get no response
is green in on you get weak
if green in off strong
is red in on and green in off very strong
destruction of the retina and nerve results in what?
monocular blindness
If you have compete cuts in one side if your LGN or V1 or optic tract what happens>
lose half of visual field (hemianopia)
partial cuts of the optic tract, LGN, or V1 results in what?
quadrantanopia
small injuries to the occipital lobe often produce small blind spots known as what?
scotomas
What does damage to the what pathway cause?
visual form agnosia- can’t recognize objects
What does damage to the how pathway cause?
can’t let them hold objects or use em
